Valve housing and method of making the same

ABSTRACT

A valve housing is composed of a pair of shell sections each of which has an open side surrounded by an edge face, and a semi-circular rib located within the open side and having a face slightly downwardly recessed from the associated edge face. The shell sections are placed together so that their edge faces abut, and these edge faces are welded to one another. The ribs are semi-circular in mutually opposite directions and thus form a circumferentially complete annular portion. Opposite this portion the housing is provided with an opening having a larger diameter than the portion, and after the shell sections have been welded together a material-removing tool is inserted through this opening and forms on the tubular portion a circumferentially complete annular welding face which is in part of stepped configuration. A seat-forming member which is annular and which is of similarly stepped configuration is then inserted through the opening and positioned on the annular welding face, and thereupon welded to the same by means of an electron beam which is admitted through the opening.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional application of the applicationSer. No. 477,493, filed June 7, 1974, now U.S. Pat. No. 3,913,887.

BACKGROUND OF THE INVENTION

The present invention is generally directed to valve housings for gatevalves and the like, and more particularly to a novel valve housingconstruction and to a method of making the same.

Valve housings of the general type with which the present invention isconcerned, and a method of effecting welding of such valve housings bymeans of directing an electron beam against the parts to be welded, arealready disclosed in my prior U.S. Pat. No. 3,473,785 which isincorporated in its entirety by reference.

In that patent I have disclosed how I can make a valve housing for agate valve or the like by utilizing two forged shell sections which areplaced into abutting engagement of their edge faces, thus forming avalve housing. The edge faces are then welded together by an electronbeam, and in the interior of the valve housing there is provided asupport composed of portions provided on the respective shell sectionsand to which a seat-forming member is also welded by an electron beamadmitted from the exterior of the valve housing.

The construction disclosed in my aforementioned U.S. patent isadvantageous for the reasons outlined therein; however, it has beenfound that further improvements are desirable for reasons of ease ofmanufacture, and for another reason which is even more important. Inparticular, it has been found that licensing authorities which must passon the acceptability of valve housings of such type frequently requirethat the welded seam be inspected for the quality of the weld bysubjecting the housing to an X-ray examination. The constructiondisclosed in my aforementioned U.S. patent cannot meet theserequirements, at least not fully, because in the regions where the edgefaces abut there were certain overlaps which existed with portions ofthe shell sections to which the annular seatforming member was welded,and this overlap made a precise control of the weld quality by X-rayingimpossible.

SUMMARY OF THE INVENTION

It is therefore a general object of the present invention to provide animprovement over the prior art.

More particularly, it is an object of the present invention to providean improved valve housing of the type in question, and an improvedmethod of making this valve housing, which meet the requirementsoutlined above, and in particular make it possible to readily andreliably examine by means of X-rays the welded seam which units theshell sections of the housing.

Another object of the invention is to assure that, while theaforementioned advantages are obtained, the possibility of welding thering-shaped valve-seat carrying member by means of electron beams fromthe exterior of the housing, is preserved.

In keeping with the above objects, and with others which will becomeapparent hereafter, one feature of the invention resides in a method ofmaking a valve housing for gate valves and the like. The methodcomprises the steps of providing a pair of shell sections which areforgings and which each have an open side bounded by an edge face, and asemi-circular rib which is located within the open side and which has aface slightly downwardly recessed from the associated edge face. Theribs are semi-circular in mutually opposite directions and one of theshell sections has in its wall opposite the open side thereof an openingof a diameter greater than the diameter defined by the ribs together.The shell sections are then placed together so that the open sides arejuxtaposed and their faces abut one another, and they are weldedtogether at the edge faces in order to form a valve housing. Thereupon,a material-removing tool --such as a milling cutter or the like-- isinserted through the opening and is used to form respective at leastsemi-cylindrical welding faces on the respective ribs, which facestogether define a circumferentially complete annular face of in partZ-shaped stepped configuration. An annular seat-forming member ofsimilarly stepped configuration is thereupon inserted through theopening and is positioned on the annular welding face, and then thevalve-seat forming member is welded to the annular welding face by meansof an electron beam which is directed into the interior of the housingthrough the opening thereof.

It is clear that during the initial operating step of making the housingfrom the shell sections, only the two shell sections are welded togetherat their juxtaposed edge faces which have previously been machined--ground, or otherwise finished-- so as to be completely planar. Thewelding of the shell sections to one another can be effected byadmitting an electron beam through one of the axially spaced inlet andoutlet openings which are provided in addition to the aforementionedopening, and during relative movement of electron beam and housing thebeam can reliably contact all portions of the housing at the interiorthereof, that is at the interface between the juxtaposed edge faces, sothat a reliable weld is obtained. Since the faces of the ribs aresomewhat recessed from the associated edge faces of the respective shellsection, the beam can pass by the ribs and the latter do not interferewith it, so that a welded seam is obtained at the edge faces of the twoshell sections which is reliable throughout.

The subsequent step of operating upon the thus created housing by meansof the aforementioned material-removing tool, assures in the first placethat the seam between the welding faces on the ribs and thecircumferential surfaces of the subsequently to be introducedseat-forming member of annular configuration can be reached when lateranother electron beam is introduced through the opening of the housingin parallelism with the central axis of this opening, which may also beconsidered a transverse opening as opposed to the axially spaced inletand outlet openings for fluid. In so doing it is important that when thematerial-removing operation is carried out, a Z-shaped steppedcircumferentially complete cylindrical annular welding surface beproduced, which at its diametrically opposite regions of intersectionwith the edge faces of the shell sections which bound the shell sectionsin longitudinal direction of the latter, has approximately double theheight due to overlapping of the ends of the semi-circular segments.These segments, which are each located to one half above and to one halfbelow the plane of the interface of the edge faces of the two shellsections, form a stepped annular welding surface of which thedouble-height diametrically oppositely located portions extendsubstantially normal to the welded-together edge faces of the shellsections in the region where they intersect with the same. This assuresa clean and reliably tight weld since overlapping welding regions --ofthe welds used for welding the shell sections together, and subsequentlyof the weld used for welding the valve-seat forming member to theannular welding surface-- is avoided.

Finally, the third essential operation is to introduce the one-pieceannular valve-seat forming member, which is also provided withsubstantially Z-shaped stepped configuration, through the transverseopening into the interior of the housing, and to place it onto thewelding surface, whereupon an electron beam is introduced through thetransverse opening in parallelism with the central axis of the same andused to weld the valve-seat forming member to the annular weldingsurface. The approximately Z-shaped circumferential welding face on thevalve-seat forming member provides for a reliable tight weldingconnection which bridges the plane of separation of the shell sectionswith strip-shaped portions at diametrically opposite locations.

The advantages of the housing according to the present invention are tobe seen in the fact that it is not only possible to produce reliablewelds at the interface of the two edge faces of the shell sections, butalso that these welds can be readily examined by X-rays, and that theformation of the weld and the subsequent X-raying are not influenced bythe fact that the annular valve-seat forming member is provided and isalso welded in place.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a vertical longitudinal section through a housing according tothe present invention;

FIG. 2 is a top-plan view of FIG. 1;

FIG. 3 is a bottom-plan view of the upper shell section of the housingin FIG. 1, after the edge faces have been machined to be planar;

FIG. 4 is a view similar to FIG. 3, but in a top-plan view of the lowershell section after the edge faces have been machined to be planar;

FIG. 5 is a horizontal section taken on line C-D of FIG. 1;

FIG. 5a is a section similar to FIG. 5, but taken on line C--C', D--D'of FIG. 1;

FIG. 6 is a vertical section taken on line A-B of FIG. 1;

FIG. 7 is a vertical section taken on line E-F of FIG. 2; and

FIG. 8 is a perspective view illustrating the annular valve-seat formingmember used in the illustrated embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawing in detail it will be seen that in FIG. 1 avertical section is shown of the finished housing. The latter iscomposed of two forged shell sections 2 and 3, namely the upper shellsection 2 and the lower shell section 3. Both of these increase indiameter from their opposite ends towards the center, as is most clearlyevident from FIG. 2. The upper shell section 2 is provided with atransverse opening 1, and FIG. 1 shows that the housing is provided atits opposite axial ends with inlet and outlet openings for fluid.

The shell sections 2 and 3 are bounded by edge faces which are mostclearly shown in FIGS. 3 and 4 and which are identified with referencenumerals 4 (for the shell section 2) and 5 (for the shell section 3),respectively. These edge faces 4 and 5 are placed into abutment with oneanother after they are first machined to be perfectly planar and extendin parallelism with the longitudinal center plane x--x (see FIG. 1); thewelding is effected by means of electron beam welding of the type and inthe manner disclosed in my aforementioned U.S. patent.

The shell section 2 is formed in its interior with an arcuatesemi-circular rib 7 which is concentric to the axis y--y along which thevalve spindle (not shown) will later move with respect to the transverseopening 17. The shell section 3 is formed with a similar transverse rib8, and the two ribs are semi-circular in mutually opposite directions(compare FIGS. 3 and 4). The height of the ribs 7 and 8 is such thattheir free faces are located slightly recessed from the respective edgefaces 4 and 5, that is they must be recessed from the center plane x--x.As onepiece annular valve-seat forming member 9 is accommodated betweenthe ribs 7 and 8 and the lateral portions of the shell sections 2 and 3,and is welded in place in the manner which will be discussedsubsequently. The member 9 may be provided with a ring-shaped seat 10that is applied to it by cold-rolling or in any other suitable manner.The members 9 and 10 are fully or almost fully prepared --machined,finished or the like-- before being welded in place.

At the opposite end portions 11 of the shell sections 2 and 3, which endportions 11 surround and define the inlet and outlet openings for thehousing, flanges 12 may be welded to the housing for connection of thehousing to corresponding flanges of pipes or the like. However, it isentirely possible to weld the end portions 11 directly to respectivepipes without requiring the use of flanges, and again it is possible touse flanges which can be connected to the end portions 11 by means ofcooperating screw threads provided on the flanges and on the endportions. Similarly, the tubular portion of the shell section 2, whereinthe opening 17 is formed, may be provided without a flange as shown, orwith a flange as diagrammatically suggested in FIG. 1 by the brokenline. If no flange is provided, then --as shown in FIG. 1-- the portionwill be provided with circumferentially spaced projections 14 in whichbores (not shown) may be formed for receiving screws or the like.

The shell sections 2 and 3 are relatively flat in their respectiveinterior, and are wider at the center than they are at the end portions11, as already pointed out earlier. This means that the height of theflow passage through the housing subsequent to the valve opening 15 isequal or at least not substantially greater than the inner diameter ofthe openings bounded by the end portions 11. The width of the shellsections 2 and 3 is approximately double the inner diameter in theregion of the end portions 11. The edge faces 4, 5 of substantiallyuniform width over the entire axial length of the respective shellsections, as a comparison of FIGS. 3-5 will readily establish.

When the edge faces 4, 5 have been finished so as to be absolutely planewith respect to the center plane x--x, the shell sections 2 and 3 areplaced together so that the edge faces 4, 5 abut in the plane x--x,whereupon the edge faces 4, 5 are welded together by means of theaforementioned electron beam, or by means of more than one of suchbeams, which are admitted through the inlet and outlet openings at theopposite axial ends of the housing. The welding takes place during arelative movement of electron beam or beams and housing. In the regionsof increased wall thickness of the housing, the relative movementbetween housing and electron beam or beams is either decreased, or thebeam energy is increased, in order to obtain a high-quality weld. Sincethe edge faces 4, 5 are only in abutting engagement, but are not blockedeither at the interior or at the exterior of the housing, the electronbeam can also be applied from the exterior of the housing and can passbetween the edge faces 4, 5 to the interior of the housing, thus forminga weld extending over substantially the entire surface area at theinterface between these edge faces 4, 5, from the outer to the inneredges 6 thereof. This seam can subsequently be X-rayed to determine itsquality and tightness, in the manner which will be discussed later.

When the shell sections 2, 3 have been welded together in the mannerjust discussed, a material-removing tool is inserted into its interiorthrough the transverse opening 17. If the opening 17 has not beenpreviously formed, then the housing is placed into an appropriate toolmachine and the latter is used to form the opening 17 in the tubularportion 13. The diameter 18 of the opening 17 must be greater than theouter diameter of the annular valve-seat forming member 9 which is to beinserted through it. A slightly smaller drill or milling cutter is usedthereafter, being inserted through the opening 17, to form first an atleast semi-cylindrical welding face 19 on the rib 7, and thereupon toform a similar semi-cylindrical stepped groove 20 in the rib 8. The endportions of the face 19 and the groove 20 overlap in the region 21 atdiametrically opposite portions at the middle of the housing andintersect the welded-together edge faces 4, 5 in these short sections21. The surface 19 and the groove 20 together thus form an annularwelding surface which is circumferentially complete and which forms asubstantially Z-shaped stepped configuration at diametrically oppositesides of the housing, and in the region of the sections 21 as double theheight 22.

The ring-shaped valve-seat forming member 9 is already shown as insertedand welded in place in the housing in FIGS. 1, 5 and 6. Itsconfiguration is shown in the perspective view of FIG. 8 and it will beseen to have an approximately Z-shaped configuration, being formed withcylindrical welding faces 23 and 24. In the diametrically oppositeregions 21a the two sectors of the faces 23, 24 overlap so as to form awelding face region of twice the height. The face 23 is welded to thesurface 19 of the rib 17, which has a corresponding circumferentiallength, whereas the face 24 is welded to the groove 20 which also has acorresponding circumferential length. The faces 23, 24 have the samediameter and thus together form an essentially cylindrical surface. Thedepth to which the member 9 can be inserted is determined by theabutment of the lower end of the member 9 with the shoulder 25 of thegroove 20. Thereupon, an electron beam 26 is admitted (see FIGS. 1 and6) in parallelism with the central axis of the opening 17, which is alsothe axis y--y of the spindle to be inserted later. Relatively circularmovement is then effected between electron beam 26 and housing, toobtain a welding of the member 9 in place.

The two welds which are thus obtained, that is the first weld whichconnects the shell sections 2 and 3 and the second weld which holds themember 9 in place, in effect extend normal to one another and contactone another only within the diametrically opposite housing portion 21.This assures an absolutely tight transition between the welds, and eachwelded seam can be controlled by X-raying without having to influence ordamage the other welded seam.

FIGS. 1 and 8 show also that the upper half of the member 9 forms acircumferentially complete annular portion the circumference of which isradially inwardly offset above the lower surface 26 which is of Z-shapedstepped configuration and has the outline of an arcuate segment. Therecessing is over most of the circumference of the upper half of themember 9, so that a recessed surface 27 is obtained which makes itpossible for the electron beam to enter without deflection into thewelding region between the surfaces 20 and 24, that is where the weld isto be established which holds the member 9 in place.

The shell sections 2 and 3 are provided midway intermediate the oppositeends 11 with inwardly bent or deformed portions 28 which are locateddiametrically opposite one another. The purpose of these portions is todeflect the edge faces 4, 5 in these regions far enough inwardly so thatthey will be intersected by the welding faces 19, 20, thereby assuringthat even in the region of these inward depressions the edge faces 4, 5have essentially the same width as elsewhere.

To control the quality of the welded seams which have been produced, theshell sections 4, 5 are first welded together with the aforementionedelectron beam or beams, and thereupon the welded seams produced areX-rayed by placing X-ray film against the housing at the exterior,keeping in mind the depressions formed at the regions 28, and thenX-rays are directed outwardly from the interior of the housing throughthe wall thereof, so that the X-rays travel past the free edges of therib 7, 8 into and through the welded seams where the edge faces 4, 5 arewelded together. The fact that the free edges of the ribs 7, 8 arerecessed from the plane x--x is of great importance not only because itprevents deflection of the electron beam which effects welding of theedge faces 4, 5 together, but also it prevents deflection of the X-rayradiation and thus permits simple and reliable X-raying of the weldedseam. Subsequently, the further operations are carried out whichculminate in the welding-in-place of the member 9. The welds holding themember 9 in place, and the welds connecting the edge faces 4, 5together, contact but do not overlap one another, thus making itpossible to obtain reliable X-ray pictures by means of which the qualityof the welds can be readily checked.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofapplications differing from the types described above.

While the invention has been illustrated and described as embodied inthe making of a valve housing for gate valves or the like, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

I claim:
 1. A method of making a valve housing comprising the steps ofproviding a pair of shell sections each having an open side bounded by aplanar edge face, and a semi-circular rib integral with the respectiveshell section, located within said open side and having an end facesubstantially parallel to the respective edge face, and displaced in adirection normal to the associated edge face from the latter, the ribsbeing semi-circular in mutual opposite directions, and one of said shellsections having in its wall opposite said open side an opening having acentral axis substantially normal to the edge face thereof and adiameter greater than the diameter defined by said ribs together;grinding said edge faces of said shell sections; placing said shellsections together with said open sides juxtaposed and said ground edgefaces abutting against each other in a plane, with said end faces ofsaid ribs located to opposite sides of said plane; welding said shellsections together at said edge faces by a weld seam; examining thethus-formed weld seam over the whole length thereof by x-rays; insertinga material removing tool through said opening and forming with itrespective at least semi-cylindrical welding faces on the respectiveribs, which together define a circumferentially annular face of in partZ-shaped stepped configuration; inserting through said opening anannular valve seat forming member of similarly substantially Z-shapedconfiguration and positioning it on said annular face; and welding saidannular valve seat forming member to said annular face by means of anelectron beam passing through said opening parallel to the central axisthereof.